A wafer etching method wherein hydrogen gas, ammonia gas or mixed gas containing one of these gases is added to sulfur hexafluoride gas to suppress the occurrence of white turbidity on the surface of the wafer at the time of etching and to enable high quality mirror polishing of the wafer. In one embodiment, a mixed gas obtained by mixing SF6 gas G1 of a bomb 31 and H2 gas G2 of a bomb 32 in a predetermined ratio is fed to a discharge tube 2 and a microwave M is generated from a microwave oscillator 4 to cause plasma discharge. Further, the entire surface of the silicon wafer W can be flattened by locally etching the surface of the silicon wafer W by an activated species gas G sprayed from the nozzle portion 20.